Atherosclerosis involving the carotid artery is a major cause of disabling transient ischemic attacks, stroke and death. This research is utilizing B-mode imaging and pulsed Doppler techniques to detect disease at the carotid bifurcation and use these methods to quantify the degree of involvement. Further by using signal processing techniques, it may be possible to determine the degree of flow disturbance that results from arterial narrowing. It is also planned to use these methods for long-term study of patients undergoing carotid enderterectomy and assess the prevalence of atherosclerosis in patients undergoing major cardiac and vascular surgery. These same methods will be used to assess the degree of flow disturbance in the femoral artery produced by aorto-iliac lesions. This information may be used for selection of the appropriate operative procedure. The ultimate goal is to develop an integrated noninvasive system that will provide both anatomical and physiologic data concerning the presence of atherosclerosis and its effects on function.